Jotul Oslo Startup and Performance Questions

[senorFrog]

Well beyond my feeble masonry skills.

Hmmmm....

 

[snowfreak]

I'm just an amateur burner but here's my .02. I have the Jotul F 600 Firelight. I have a 20ft vertical run of 6" prefab chimney all on the interior of the house with the exception of 4ft above roof. When I first started the stove it would act just like yours. I thought maybe my pine kindling was not dry enough. So I tried some in my outdoor firepit and that took off like gasoline was in it. Definetly not the kindling. So the next fire I kept the side door open a pretty good crack and the fire roared to life in no time, had the air inlet all the way open shut the door and the fire died down to nothing. Opened the door a crack and wham the fire was right back to a full roar. So I added some hard wood onto the top of the kindling and kept the door cracked for 15 min shut the door, kept the air inlet all the way open and the fire died a bit but was roaring really well. When I start a fire from scratch that's how I do it now. Keep the door cracked for 15 min then shut the door with the air inlet wide open. As far as the high wood consumption, I can pack my stove full and unless I turn the air inlet all the way down it will turn whatever is in it to coals in 4 hours. For an extended burn I get things going real well, I leave the air control just below half and make sure the wood is well charred (about an hour) and then shut the air control all the way down. The description you gave about 1sec with a burst of flames and 2 sec without sounds exactly what mine looks like when I have the air control all the way down. I'm not so sure your problem is a draft problem or just getting used to how your stove operates. I have just about the perfect chimney set up and experienced similar problems as you. I would say if the stove is new to you try giving it some more learning time. I kind of chuckled when someone made the comment about the ash door open and the blow torch sound. My first few ash cleanings I would race to get the ash pan out very quickly to prevent the blow torch effect. Then I discovered if I shoveled all the coals to the back and sides of the stove off the grate where the air would come in, I could take my time with the ash pan. Just part of learning curve I guess. Happy burning.

 

[senorFrog]

MSG, manual states warranty is invalid id using ash door to start fire. It warns against possible overfiring when using front or side door. Doesn't come outright and say you shouldn't.

According to the website however (which admittedly is weaker than the manual)...

http://www.jotul.us/Content/StandardPage____2710.aspx

If it is difficult to start the fire the reasons could be:

Not enough air: Open the air valves. Sometimes the door must be opened (approx. 1 cm gap). Make sure that the damper is in open position.
Bad kindling: Use small pieces of split kindling together with crumbled newspaper, and add larger pieces. Remember: The smaller the better, the dryer the better.
Down draft/cold chimney: Heat up the chimney by twisting some newspaper into a torch and hold it up into the stove until the draft is reversed.

Do you know of any reason why I should not do this? Just for starting, say 45-60 minutes, until I get good bed of coals.

 

[senorFrog]

Thanks snow for taking the time to write that all up! Part of this is learning curve. Not my chimney issues, but me. I'm used to an old franklin which would burn a whole tree if I could fit in there.

 

[MountainStoveGuy]

I'm just an amateur burner but here's my .02. I have the Jotul F 600 Firelight. I have a 20ft vertical run of 6" prefab chimney all on the interior of the house with the exception of 4ft above roof. When I first started the stove it would act just like yours. I thought maybe my pine kindling was not dry enough. So I tried some in my outdoor firepit and that took off like gasoline was in it. Definetly not the kindling. So the next fire I kept the side door open a pretty good crack and the fire roared to life in no time, had the air inlet all the way open shut the door and the fire died down to nothing. Opened the door a crack and wham the fire was right back to a full roar. So I added some hard wood onto the top of the kindling and kept the door cracked for 15 min shut the door, kept the air inlet all the way open and the fire died a bit but was roaring really well. When I start a fire from scratch that's how I do it now. Keep the door cracked for 15 min then shut the door with the air inlet wide open. As far as the high wood consumption, I can pack my stove full and unless I turn the air inlet all the way down it will turn whatever is in it to coals in 4 hours. For an extended burn I get things going real well, I leave the air control just below half and make sure the wood is well charred (about an hour) and then shut the air control all the way down. The description you gave about 1sec with a burst of flames and 2 sec without sounds exactly what mine looks like when I have the air control all the way down. I'm not so sure your problem is a draft problem or just getting used to how your stove operates. I have just about the perfect chimney set up and experienced similar problems as you. I would say if the stove is new to you try giving it some more learning time. I kind of chuckled when someone made the comment about the ash door open and the blow torch sound. My first few ash cleanings I would race to get the ash pan out very quickly to prevent the blow torch effect. Then I discovered if I shoveled all the coals to the back and sides of the stove off the grate where the air would come in, I could take my time with the ash pan. Just part of learning curve I guess. Happy burning.

True snowfreak, a learning curve is definalty in place. But, we knew Senior Frogs venting situation months ago, and suspected a problem then. Now the problem is showing up. The Oslo is the best drafting stove Jotul makes, followed by the 3cb. The most draft sensitive stove they make is the castine, followed by the firelight.

Elk, we disagree alot on the penalties for elbows. Jotul says there first one is free. But its only a guidline. I dont think in real life you get a 10' penalty for 2 90's, if that was the case i would have alot of stoves out there with a negative chimney.

Seniorfrog, we made some suggestions last time on how to get that chimney taller, via the anchor plate, and the extendaflue. I would consider either of those options. Also i would consider using double wall interior pipe, it will keep the heat in better, expecially at that elbow and horizontal run. The Olso book says no more then 36" horizontal witha 10' maximum of total stove pipe.

 

[senorFrog]

Seniorfrog, we made some suggestions last time on how to get that chimney taller, via the anchor plate, and the extendaflue. I would consider either of those options. Also i would consider using double wall interior pipe, it will keep the heat in better, expecially at that elbow and horizontal run. The Olso book says no more then 36" horizontal witha 10' maximum of total stove pipe.

Already using double wall interior stove pipe. I'm less than 10' on the total stove pipe. I know about the long run, but out of my hands, working with an existing chimney, not something I designed.

Thanks for your help!

 

[MountainStoveGuy]

I understand, so, the cure for the long run of horizontal is more verticle. Or learn to live with it the way it is. Your asking for a fix, and we are givin it to ya

 

[senorFrog]

I understand, so, the cure for the long run of horizontal is more verticle. Or learn to live with it the way it is. Your asking for a fix, and we are givin it to ya

You sure are! Thanks boss.

 

[elkimmeg]

MSG if the manufacture gives the first 90. I have no problem with that. I was going according to code whic does state as the math 5' per elbow so reduce that height by 5'

] But in a poor draft situation minium chimney height, even that may not cut the mustard.

Oitside enviremental possibilities like a large tall tree, hill. a taller neighboring home, or even taller sections of his home. Presurization isues within the home? all could be a causes for less that good draft and have nothing to do with the chimney . Ash cleanout door leaking? more than one ash cleanout doors leaking? exterior ash dumkp door leaking profusly?

 

[Todd]

Can that thimble be cut back some to accommodate a couple 45 elbows? Or does that screw with the clearance to combustibles.
Even if you cant cut the thimble it looks like you still have enough room to make 2 45's work?

 

[senorFrog]

Total stack height is 15 feet. Four feet of that is the vertical stove pipe leading to horizontal run. The remaining 11 feet is chimney.

If I wanted to get to 20 feet, assuming I can count the four feet of stove pipe as part of the stack height, I'd need to add another five feet.

Todd, Thimble can not be easily cut. Would have to be sent out for a to be professionally cut. There may be a minimum wall clearance issue that I'm not aware of too. When installing we laid out 2 45's initially. We would have had to put the stove way over to the right. That impacted the 18 inch clearance to the stairs , looked really goofy and didn't save much horizontal run (less than six inches).

 

[MountainStoveGuy]

So, subtract 5' for one of those elbows, and 1 foot for every verticle foot. thats a 9' deduction on your 15' chimney, so you have a net of a 6' chimney. (of course this is not hard line rules, just a rule of thumb. But it shows it needs help, alot of help.

 

[senorFrog]

Horizontal run is about 4', so that's four feet there. The second 90 costs me another 5'. Per manual I need a net height after deductions of 14'. So 14' + 4' + 5' = 23'. Target height of 23' - existing 15' = adding another 8'. That would make my unsupported chimney height 16' (because as you can see in the pics this off a flat roof). I don't know if that's possible or allowable under builing codes. Any masons out there?

and 1 foot for every verticle foot.

MSG, did you mean horizontal? If verticle, then verticle foot of what? The stove pipe run?

 

[MountainStoveGuy]

If you extend it with pipe you can play with it untill it gets right, the extenda flue would be lighter then masonry as well, but you cant adjust it once you buy it. You might also consider a exausto fan. I hear they work ok.

 

[cbrodsky]

Total stack height is 15 feet. Four feet of that is the vertical stove pipe leading to horizontal run. The remaining 11 feet is chimney.

If I wanted to get to 20 feet, assuming I can count the four feet of stove pipe as part of the stack height, I'd need to add another five feet.

Todd, Thimble can not be easily cut. Would have to be sent out for a to be professionally cut. There may be a minimum wall clearance issue that I'm not aware of too. When installing we laid out 2 45's initially. We would have had to put the stove way over to the right. That impacted the 18 inch clearance to the stairs , looked really goofy and didn't save much horizontal run (less than six inches).

First, really nice looking setup - like the brick work on three sides.

Looking at the picture, it seems you could at least directly replace your 90 with two 45s and end up with a slightly shorter horizontal run. Even if you don't add a straight section between the two 45s, this would still be an improvement over a hard 90. But it looks like you could definitely come from the thimble with a 45 degree, then a small straight section, and then another 45 to go down to the stove. All combined, I think it would be enough of an improvement to try.

I know double wall isn't cheap, but neither are some of the other options under consideration. And my guess is if you don't like the results, you could always sell your spare double wall parts on ebay.

-Colin